Revert of Change SkShader;asFragmentProcessor signature to no longer take skpaint\grcolor*

src/gpu/effects/GrMatrixConvolutionEffect.cpp

Index: src/gpu/effects/GrMatrixConvolutionEffect.cpp
diff --git a/src/gpu/effects/GrMatrixConvolutionEffect.cpp b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
index 76fa6420ab45451e6fb606d0112d2166b58c948d..c5a7fb7836cbae1c4fc3b87c32703bf5fc20d1a6 100644
--- a/src/gpu/effects/GrMatrixConvolutionEffect.cpp
+++ b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
@@ -222,7 +222,7 @@
 
 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMatrixConvolutionEffect);
 
-const GrFragmentProcessor* GrMatrixConvolutionEffect::TestCreate(GrProcessorTestData* d) {
+GrFragmentProcessor* GrMatrixConvolutionEffect::TestCreate(GrProcessorTestData* d) {
     int texIdx = d->fRandom->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx :
                                           GrProcessorUnitTest::kAlphaTextureIdx;
     int width = d->fRandom->nextRangeU(1, MAX_KERNEL_SIZE);